14.5.2.1 To Disable a User with Delegated Administrator Console

In the Delegated Administrator Console, it is not possible to merely
temporarily inactivate a user. You must remove calendar services from the
user. To do this, select the user from the User List page. In the Properties
for this user, delete the service package with calendar service in it. This
disables the user for calendar, including setting the user's icsStatus to inactive.

Note –

If the package also contains other services, you will have to
reassign those services using another package that does not contain calendar.